Potassium Nitrate (KNO3) is much used in low explosives and incindiaries,
(black powder for example) and will find much uses as oxidizer in ignitors and such.
This is in the synthesis section, but it was more of a purification then anything else.
You still need a source of nitrate, it was the discovery of just that, that led to the creation of this page.
Et voila, here it is. A stable in an old farm. The stuff is just growing on the walls here :)
A close-up. How come there's KNO3 growing on the walls here? Well ...
The room this picture was taken in used to be a stable for animals over the last century.
The manure of these animals got a hold in the porous ground, and got all worked up by various bacterias
(do a google search on this subject if you want more details)
The nitrate was the end form, and it was just there, enriching the soil.
Now, in this warm weather, the moisture in the ground is going up in the walls, where it
evaporates, leaving the KNO3 behind in a very fine crystaline form.
This is all that I could gather from the walls, not much, but hey, it's free :)
As you no doubt noticed, it's all dirty, and far from pure.
Alot of paint and dust came along with the nitrate.
For it to be usefull, it must be purified. The picture below shows what is needed.
I placed the raw potassium nitrate in the white filter, while I was heating up 200 ml water.
Next, I poured the hot water gently over the raw nitrate, giving it the chance to dissolve.
Better do it in multiple steps, letting the water run trough and then add some more.
Do this untill the 200 ml water is used up (run the very last bit down the sides of the filter paper)
Next is an unsharp picture, but it shows what it's supposed to show. Volume of the water increased !!
Also remember the dirt in the filter is not completely dry yet, so I guess there would be about 275 ml in total.
In the next step we add the same amount of alcohol to the nitrate solution, to make the nitrate precipate.
This is a slightly exothermic process, but nothing to be worried about.
Put the mix in the fridge anyway, and let it cool down to less then 10�C.
Next step is to filtrate the potassium nitrate (I used the brown filter to make it show better on pics)
In the next picture, you see everything on a row.
From left to right we have the dirt, the KNO3 and some of the alcohol/water mix.
I boiled down the alcohol and water mix to about 50 ml again, in order to get more KNO3 out of it.
When volume was decreased enough I added the same amount of alcohol again and refiltered.
The combined yield was about 75 grams. I weighed the impurities too, that was 37 grams.
The product in this form is a super fine crystaline, nice and pure white.
And "Why do this when you can buy it pure and cheap in 25 kg bags?" Simple, for the fun of it :)
BACK